Photographic exposure tester



H. R. JOHNSON 2,126,332

PHOTOGRAPHIC EXPOSURE TESTER I Original Filed June 11, 1936 2 Sheets- Sheet 1 Inventor By mm.

Attorneys Aug. 9, 1938.

Aug. 9, 1938. H. R. JOHNSON PHOTOGRAPHIC EXPOSURE TESTER Original Filed June 11, 1956 2 Sheets-Sheet 2 Attorneys Patented Aug. 9, 1938 UNITED STATES PATENT OFFICE Application June 11, 1936, Serial No. 84,739 Renewed June '25, 1938 3 Claims.

This invention relates to an apparatus for testing photographic exposures and a salient object of the present invention is to provide a device which will render possible the making of a num- 5 her of test exposures on a single sensitized test sheet to the end that a great deal of time will be saved in determining the proper period of exposure as well as a saving in the use of costly photographic paper.

A further object of the invention is to provide a device of this character characterized by simplicity of construction to the end that the device may be produced to retail at a nominal cost.

The invention together with the objects and advantages will be best understood from a study of the following description taken in connection with the accompanying drawings wherein- Figure 1 is a top plan view of the invention.

Figures 2, 3 and 4 are sectional views taken substantially on the lines 2-2, 3-4, and 4-4 respectively of Figure 1.

Figure 5 is a perspective view of a guide plate.

Figure 6 is a plan view of paper which has been exposed for test purposes,

In the preferred embodiment thereof, the testing apparatus comprises an oblong base plate 5 formed of metal or other suitable material. Secured to one face of the base plate 5 adjacent one end of the base plate and adjacent opposite 30 longitudinal edges thereof are spring latch members 6 adapted to engage the opposite side edges of a guide member 1 which at one end is hinged as at 8 to the base plate 5.

Guide member 1 preferably consists of an oblong plate of metal or other suitable material provided intermediate its end with an elongated slot or opening 9. At its opposite longitudinal edge the guide plate I is provided with inturned flanges presenting internal guide channels in.

40 A slide ll of metal or other suitable material has its opposite longitudinal edges working in the guide channels l as shown in Figure 1 and is provided with an opening or window I2. Also to facilitate manipulation of the slide II the same 45 is provided on the top side thereof and adjacent one end thereof with a suitable handle iii.

For securing the slide H at the desired adjustment there is provided inwardly from one edge of the base plate a rod or the like ll provided 50 at intervals with notches or seats IS. A spring retaining finger i6 is anchored at one end transversely to the top of the slide II and has a free end I6a suitably bent'and curved to engage a selected seat or notch It for securing the slide ll, reieasably, at the desired adjustment.

-Also, the plate 5 at the edge thereof adjacent which the bar I4 is provided has on its upturned. face a series of numbers as shown starting at one and increasing by one up to six, although it will be understood that these numbers 'will vary in extent as determined by the size of the device and the number of exposure tests to be made.

In actual practice, and when a test strip is to be exposed, the slide it is placed with the end thereof in line with the ends of the base 5 and the guide plate I. By means of the handle or knob l3 slide 1 I and guide I are swung relative to the base 5 as a unit at the hinge 8. With the device properly positioned on the projection board of an enlarger the enlarger light can then be turned on and the rectangular block or mat I! on base 5 centered under that portion of the projected negative which appears to be the best for test purposes. The light is then turned off. The sensitized paper I8 is then placed and the mat H on theguide l and slide ll then closed down on the paper It, clips 6 serving to hold the parts in this last mentioned position. The slide II is then slid to the left (see Figure 1) until the end "5a of finger it engages in the first notch l5 of bar l4, or in other words the slide it is placed in the position shown in Figure 1. The first exposure is now made and after each exposure the slide H is slid toward the right (see Figure 1) to engage the finger end 16a in the next succeeding notch l5 and this operation is continued until all exposures have been made. When all the exposures have been made, guide 1 with slide H is swung upwardly relative to the base 5 and the strip I8 is then removed and developed. Obviously, after the test paper l8 has been developed a proper selection can then be made of exposure for the paper for printing purposes.

Having thus described the invention whatis claimed is:

1. An apparatus of the character described comprising a base plate, a guide plate hinged at one end to the base plate and provided with an elongated opening therein, said guide plate being provided with spaced parallel guide channels on one side thereof, and a slide operating on the guide plate between said channels and provided with an opening of less size than the opening in the guide plate and adapted to be brought to various positions on the guide plate and obtain an exposure therethrough at difierent parts on the sensitized paper, and spring latch members on the base plate adjacent the end thereof remote from said hinge and engageable with the sides of the guide plate for releasably retaining the guide plate in a positioin parallel to the base plate. a rod provided on said base plate adjacent to and parallel with one longitudinal edge of the base plate, said rod being provided with a series of spaced notches, and a spring iinger on said slide having an end engageable with the notches for securing the slide at the desired adjustment on the guide plate.

2. An apparatus of the character described comprising a base plate. a guide plate hinged at one end to the base plate and provided with an elongated opening therein; said guide plate being provided with spaced parallel guide channels on one side thereof, and a slide operating on the guide plate between said channels and provided with an opening of less size than the opening in the guide plate and adapted to be brought to various positions on the guide plate and obtain an exposure therethrough at diiferent parts on the sensitised paper. and spring latch members. on the base plate adjacent the end thereof remote from said hinge and engageable with the sides of the guide plate for releasably retaining the guide plate in a position parallel to the base plate. a rod provided on said base plate adjacent to and parallel with one longitudinal edge of the base plate, said rod being provided with a series of amass:

spaced notches, a spring tinger on said slide having an end engageable with the notches ior securing the slide at the desired adjustment on the guide plate. said slide being also provided adiacent one end thereof with a handle to facilitate manipulation of the guide plate and slide as a unit and also to facilitate sliding of the slide relative to the guide plate.

3. A photographic exposure tester comprising a base plate, a guide plate hinged at one end thereof to one end of the base plate, said guide plate being provided with an elongated opening, and also being provided at its longitudinal edges with guide channels extending substantially for the full length of the guide plate, a slide having edge portions working in said guide channels and provided with an opening 0! a size less than the opening in the guide plate, a rod mounted on said base plate adjacent to and parallel with one longitudinal edge of the base plate, said rod being provided with a series 0! spaced notches, and a laterally extending spring finger on said slide having a free end engaging said rod and couperable with said notches for securing the slide at the desired position of adjustment on the guide Plate.

HARRY R. JOHNSON. 

